The primary goals and function of the MDRC Animal Phenotyping Core are to provide expert consultation, state-of-the art equipment and technical services that are critical for the detailed metabolic phenotyping of rodent models of diabetes and obesity. The goals of the Animal Phenotyping Core are to: 1. Provide expert consultation and training to MDRC investigators regarding phenotyping strategies and experimental design to characterize rodent models of diabetes and related metabolic diseases. 2. Provide MDRC investigators with the capability for sophisticated, standardized metabolic phenotyping of rodent models relevant to diabetes, obesity and associated metabolic diseases. 3. Provide expert aid in the analysis and interpretation of data arising from services offered in the APC. 4. Develop new techniques and acquire new technologies for rodent, whole animal metabolic phenotyping in response to the needs of MDRC investigators. The Animal Phenotyping Core provides a comprehensive, convenient and cost-effective menu of platforms that includes: a) Glucose homeostasis and metabolic clamp studies in rats and mice, b) Whole animal metabolic assessment. The CLAMS apparatus and other systems are used to examine metabolic rate, respiratory quotient, food consumption, and locomotor activity in rodent models, c) Body composition is measured by NMR. d) Radiotelemetric monitoring. Systems are in place for remote, chronic monitoring of cardiovascular parameters and core body temperature in rats and diurnal running wheel behavior in mice, e) Ingestive behavior. Meal microstructure and reinforcing properties of dietary constituents are measured in either home-cage or operant-conditloning paradigms, f) Automated blood/body fluids sampling and infusion in freely behaving, unstressed rodents. Altogether, the Animal Phenotyping Core provides consultation and advice on experimental design, reliable data from a range of validated assays and essential data analysis relevant to the needs of multiple investigators in the MDRC